Programmable logic controller, engineering tool, and engineering tool program

ABSTRACT

A programmable logic controller executes an SFC program including a plurality of blocks, each including a step indicating an operation output and a transition indicating a transition condition. The programmable logic controller includes an SFC device data collecting unit for collecting device data of a device included in an active step for each scan at the time when the SFC program is executed, an SFC device data storing unit for storing the data collected by the SFC device data collecting unit and an SFC device data outputting unit for outputting the data stored in the SFC device data storing unit to a memory card as a file for each of the steps or the blocks.

FIELD

The present invention relates to a programmable logic controller, anengineering tool, and an engineering tool program by whichtroubleshooting can be easily performed.

BACKGROUND

Conventionally, there has been a problem in a programmable logiccontroller that it takes time to perform troubleshooting in a case wherea malfunction of a sequential function chart (SFC) program has beencaused by an incorrect operation of a device value.

Patent Literature 1 discloses a programmable logic controller in whichan SFC program and an output state of a device in the SFC program can beconfirmed on a single screen for easy troubleshooting.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open No.2001-195108

SUMMARY Technical Problem

However, with a method disclosed in Patent Literature 1 described above,since a communication time between the programmable logic controller andthe engineering tool is longer than an execution time of the SFCprogram, not all the device outputs within a step can be displayed.Also, in a case where the malfunction of the SFC program has occurred,with the method disclosed in Patent Literature 1, only the currentdevice output state is displayed. Therefore, there has been a problem inthat an operation process of the device cannot, be retroactivelyconfirmed.

The present invention has been made in consideration of the aboveproblems. A purpose of the present invention is to obtain a programmablelogic controller which can display all device outputs in a step and canretrospectively confirm an operation process of a device.

Solution to Problem

In order to solve the problems and achieve the object, according to anaspect of the present invention, there is provided a programmable logiccontroller for executing a sequential function chart program including aplurality of blocks, each including a first basic unit indicating anoperation output and a second basic unit indicating a transitioncondition, the programmable logic controller including: a device datacollecting unit to collect device data of a device included in an activefirst basic unit for each scan at the time when the sequential functionchart program is executed; a device data storing unit to store the datacollected by the device data collecting unit; and a device dataoutputting unit to output the data stored in the device data storingunit to a storage medium as a file for each of the first basic units orthe blocks.

Advantageous Effects of Invention

A programmable logic controller according to the present inventionobtains an effect that the programmable logic controller can display aildevice outputs in a step and can retrospectively confirm an operationprocess of a device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating configurations of a programmable logiccontroller and an engineering tool according to a first embodiment ofthe present invention.

FIG. 2 is a diagram illustrating a hardware configuration of theprogrammable logic controller according to the first embodiment.

FIG. 3 is a diagram illustrating a hardware configuration of aninformation processing apparatus that realizes the engineering toolaccording to first embodiment.

FIG. 4 is a diagram illustrating a configuration of an SFC programexecuted by the programmable logic controller according to the firstembodiment.

FIG. 5 is a flowchart illustrating a flow of a device data collectionoperation of the programmable logic controller according to the firstembodiment.

FIG. 6 is a flowchart illustrating a flew of SFC program executionprocessing of the programmable logic controller according to the firstembodiment.

FIG. 7 is a flowchart illustrating a flow of block start processing ofthe programmable logic controller according to the first embodiment.

FIG. 8 is a diagram schematically illustrating a timing of datacollection by the programmable logic controller according to the firstembodiment.

FIG. 9 is a diagram illustrating exemplary troubleshooting by theengineering tool according to first embodiment.

FIG. 10 is a diagram illustrating exemplary troubleshooting by theengineering tool according to first embodiment.

FIG. 11 is a diagram illustrating exemplary troubleshooting by theengineering tool according to first embodiment.

FIG. 12 is a diagram illustrating configurations of a programmable logiccontroller and an engineering tool according to a second embodiment ofthe present invention.

FIG. 13 is a diagram illustrating an exemplary SFC parameter settingscreen of the engineering tool according to the second embodiment.

FIG. 14 is a flowchart illustrating a flow of a device data collection,operation of the programmable logic controller according to the secondembodiment.

FIG. 15 is a flowchart illustrating a flow of block start processing ofthe programmable logic controller according to the second embodiment.

DESCRIPTION OF EMBODIMENTS

A programmable logic controller, an engineering tool, and an engineeringfool program according to embodiments of the present invention aredescribed in detail below with reference to the drawings. The presentinvention is not limited to the embodiments.

First Embodiment

FIG. 1 is a diagram illustrating configurations of a programmable logiccontroller and an engineering tool according to a first embodiment ofthe present invention. A programmable logic controller 1 according tothe first embodiment includes a device data collection function unit 2which collects device data and an SFC monitor unit 3 which monitors anSFC program including a step which is a first, basic unit indicating anoperation output and a transition which is a second basic unitindicating a transition condition and transmits the monitoring result toan engineering tool 12. Further, the programmable logic controller 1includes an SFC program executing unit 4 which executes the SFC program,an SFC device analysis check unit 6 which is a device analysis checkunit for confirming whether a device in the step has been analyzed, anSFC device analyzing unit 7 which is a device analyzing unit foranalyzing the device data in the step at the time when the programmablelogic controller 1 has been turned on or after the program in the stephas been executed, an SFC device data collecting unit 8 which is adevice data collecting unit for collecting a device output state at thetime when the step is activated, an SFC device data storing unit 9 whichis a device data storing unit for storing the collected device outputstate, and an SFC device data outputting unit 10 which is a device dataoutputting unit for performing file outputting the device output statestored in the SFC device data storing unit 9 to a memory card 11 whichis a storage medium for each step. The SFC device data storing unit 9has a ring buffer structure, and old information is rewritten to newinformation in order. The storage medium for storing the device outputstate is not limited to the memory card 11.

FIG. 2 is a diagram illustrating a hardware configuration of theprogrammable logic controller according to the first embodiment. Theprogrammable logic controller 1 includes an operation device 21 forexecuting a program, a memory 22 used for a work area by the operationdevice 21, a storage device 23 for storing a program and data, a memorycard writer 24 for recording information in the memory card 11, and acommunication device 25 for communicating with the engineering tool 12.A central processing unit (CPU) can be applied to the operation device21. A random access memory (RAM) can be applied to the memory 22. Anon-volatile semiconductor memory can be applied to the storage device23. Note that the memory card writer 24 may be externally attached tothe programmable logic controller 1.

The operation device 21 uses the memory 22 as the work area and executessoftware so as to realize the device data collection function unit 2,the SFC program executing unit 4, the SFC device analysis check unit 6,the SFC device analyzing unit 7, and the SFC device data collecting unit& illustrated in FIG. 1. Also, a plurality of operation devices and aplurality of memories may cooperate to execute the above functions. TheSFC monitor unit 3 is realized by the operation device 21 and thecommunication device 25. The SFC device data storing unit 9 is realizedby the storage device 23. The SFC device data outputting unit 10 isrealized by the memory card writer 24.

As illustrated in FIG. 1, the engineering tool 12 includes an SFC outputfile reading unit 13 which reads a file from the memory card 11, an SFCdisplay unit 14 which superimposes the device data read by the SFCoutput file reading unit 13 on the SFC program and displays the data,and a monitoring result displaying unit 15 which receives the monitoringresult of the SFC program from the programmable logic controller 1 anddisplays the result.

FIG. 3 is a diagram illustrating a hardware configuration of aninformation processing apparatus that realizes the engineering toolaccording to first embodiment. An information processing apparatus 30includes an operation device 31 for executing a program, a memory 32used for a work area by the operation device 31, a storage device 33 forstoring an engineering tool program 38 and data, a display device 34 fordisplaying information, an input device 35 which is a user interface fora user to input information, a memory card reader 36 for readinginformation from the memory card 11, and a communication device 37 forcommunicating with the programmable logic controller 1. A centralprocessing unit (CPU) can be applied to the operation device 31. Arandom access memory (RAM) can be applied to the memory 32. Anon-volatile semiconductor memory or a hard dish drive can be applied tothe storage device 33. A liquid crystal display can be applied to thedisplay device 34. A keyboard and a mouse can be applied to the inputdevice 35. The memory card reader 36 may be externally attached to theinformation processing apparatus 30. It is not necessary for the displaydevice 34 and the input device 35 to be housed in a casing integratedwith the operation device 31, the memory 32, and the storage device 33.

In the information processing apparatus 30, the operation device 31executes the engineering tool program 38 stored in the storage device 33by using the memory 32 as a work area so as to be the engineering tool12. That is, the SFC display unit 14 illustrated in FIG. 1 is realizedby executing the engineering tool program 38 stored in the storagedevice 33 by using the memory 32 as the work area by the operationdevice 31. Also, a plurality of operation devices and a plurality ofmemories may cooperate to execute the above functions. The SFC outputfile reading unit 13 is realized by the memory card reader 36. Themonitoring result displaying unit 15 is realized by the operation device31, the display device 34, and the communication device 37.

FIG. 4 is a diagram illustrating a configuration of the SFC programexecuted by the programmable logic controller according to the firstembodiment. An SFC program 40 is described in a description format of acontrol specification in which a series of a control operations isdivided into a plurality of steps and an operation order and anoperation condition of the program can be clearly expressed. The SFCprogram 40 includes three blocks, i.e., a block [1] 41, a block [2] 42,and a block [3] 43. The block [1] 41 includes a plurality of steps suchas a step [1], a step [2], a step [3] . . . , and a plurality oftransitions. Each step is a first basic unit forming the block andindicates an operation output. Each transition is a second basic unitforming the block and indicates a condition to move to the next step. Ifa transition condition cl is satisfied at the time when the step [1] isactive, the step [2] becomes active, and the step [1] becomes inactive.If a transition condition c2 is satisfied at the time when the step [2]is active, the step [3] becomes active, and the step [2] becomesinactive. If a transition condition c3 is satisfied at the time when thestep [3] is active, the step [3] becomes inactive, and the next stepbecomes active.

The block [2] 42 includes a plurality of steps such as a step [11], astep [12], a step [13], . . . . If a transition condition c11 issatisfied at the time when the step [11] is active, the step [12]becomes active, and the step [11] becomes inactive. If a transitioncondition c12 is satisfied at the time when the step [12] is active, thestep [13] becomes active, and the step [12] becomes inactive. If atransition condition c13 is satisfied at the time when the step [13] isactive, the step [13]becomes inactive, and the next step becomes active.

The block [3] 43 includes a plurality of steps such as a step [21], astep [22], a step [23], . . . . If a transition condition c21 issatisfied at the time when the step [21] is active, the step [22]becomes active, and the step [21] becomes inactive. If a transitioncondition c22 is satisfied at the time when the step [22] is active, thestep [23] becomes active, and the step [22] becomes inactive. If atransition condition c23 is satisfied at the time when the step [23] isactive, the step [23] becomes inactive, and the next step becomesactive.

An operation of the programmable logic controller 1 according to thefirst embodiment is described. FIG. 5 is a flowchart illustrating a flowof a device data collection operation of the programmable logiccontroller according to the first embodiment. In step S11, the SFCprogram executing unit 4 performs initial processing. In step 312, theSFC program executing unit 4 performs SFC program execution processing.In step S13, the SFC program executing unit 4 performs end processing.The processing in steps S12 and S13 is executed in one scan which is anoperation cycle of the programmable logic controller 1.

FIG. 6 is a flowchart illustrating a flow of the SFC program executionprocessing of the programmable logic controller according to the firstembodiment. In the SFC program execution processing, loop processing isperformed by the number of blocks in the SFC program. In the loopprocessing, block start processing is performed in step S21. Afterlooping by the number of blocks in the SFC program, the SFC programexecuting unit 4 terminates the SFC program execution processing.

FIG. 7 is a flowchart illustrating a flow of the block start processingof the programmable logic controller according to the first embodiment.In the block start processing, the loop processing is performed by thenumber of steps in the block. In the loop processing, the SFC programexecuting unit 4 determines in step S31 whether the step in the SFCprogram is active. If the step in the SFC program is not active, theresult in step S31 is No, and the loop processing is terminated. Then,the loop processing is performed for the next step. If the step in theSFC program is active, the result in step S31 is Yes, and the SFCprogram executing unit 4 performs the operation output in the step instep S32.

Subsequently, in step S33, the SFC device analysis check unit 6determines whether the device in the step has been analyzed. If thedevice has been analyzed, the result in step S33 is Yes, and theprocedure proceeds to step S35. If the device has not been analyzed, theresult in step S33 is No, and the SFC device analyzing unit 7 analyzesthe device in the step in step S34. When the SFC device analyzing unit 7analyzes the device in the step, a storage region for the analyzed stepis formed in the SFC device data storing unit 9. Since the SFC devicedata storing unit 9 has a ring buffer structure, in a case where thereis no free space in the storage device 23, the oldest storage region inthe SFC device data storing unit 9 is rewritten to a storage region forthe step in which the device is newly analyzed. In step S35, the SFCdevice data collecting unit 8 makes the SFC device data storing unit 9store the device output state in the step. After looping by the numberof steps in the SFC program, the SFC device data collecting unit 8terminates the processing.

Through the above processing, the SFC device data collecting unit 8specifies the active step in the SFC program and makes the SFC devicedata storing unit 9 store the device data.

FIG. 8 is a diagram schematically illustrating a timing of datacollection by the programmable logic controller according to the firstembodiment. In a first scan, since a step [1] is active at the time whenthe scan starts, the SFC device data collecting unit 8 stores devicedata of the step [1] in a storage region 91 for the step [1] in the SFCdevice data storing unit 9. In a second scan, a transition condition ais satisfied during the scan, the step [1] becomes inactive, and a step[2] is active. However, since the step [1] is active at the time whenthe scan starts, the SFC device data collecting unit 8 stores the devicedata of the step [1] in the storage region 91 for the step [1] in theSFC device data storing unit 9. In a third scan, a transition conditionb is satisfied during the scan, the step [2] becomes inactive, and thestep [3] is active. However, since the step [2] is active at the timewhen the scan starts, the SFC device data collecting unit 8 stores thedevice data of the step [2] in a storage region 92 for the step [2] Inthe SFC device data storing unit 9. In a fourth scan, since the step [3]is active at the time when the scan starts, the SFC device datacollecting unit 8 stores device data of the step [3] in a storage region93 for the step [3] in the SFC device data storing unit 9.

The device data stored in the SFC device data storing unit 9 is outputto the memory card 11 by the SFC device data outputting unit 10 when thestep is inactive. As an example, the device data of the step [1] storedin the storage region 91 for the step [1] is output to the memory card11 by the SFC device data outputting unit 10 after the third scan. Inthe memory card 11, the device data is stored as a file in units ofsteps or blocks.

When troubleshooting is performed by using the engineering tool 12, anoperation process of the device is retroactively confirmed from a placein the SFC program where an incorrect operation has occurred to specifythe place where the incorrect operation has occurred. When the SFCmonitor unit 3 detects that the incorrect operation has occurred in thestep [3] in the SFC program, the monitoring result displaying unit 15displays the monitoring result on the engineering tool 12. Therefore,the user starts troubleshooting from the step [3] in the SFC program.FIGS. 9, 10, and 11 are diagrams illustrating exemplary troubleshootingby the engineering tool according to the first embodiment. First, thedevice data in the step [3] in the SFC program is read from the memorycard 11 by the SFC output file reading unit 13 and is displayed on theSFC display unit 14. In FIG. 9, a device data display screen 53 In thestep [3] is illustrated. From the device data display screen 53 in thestep [3] in the SFC program, it can be confirmed that the incorrectoperation occurs when a value of a device D1 is larger than 120 and thatthe value of the device D1 is 130.

Next, in the SFC program, the device data in the step [2], which is thestep preceding the step [3], is read from the memory card 11 by the SFCoutput file reading unit 13 and is displayed on the SFC display unit 14.In FIG. 10, a device data display screen 52 in the step [2] isillustrated. From, the device data display screen 52 in the step [2], itcan be confirmed that the value of the device D1 has reached 130 as aresult of adding 20 to the device D1.

Next, in the SFC program, the device data in the step [1], which is thestep preceding the step [2], is read from the memory card 11 by the SFCoutput file reading unit 13 and is displayed on the SFC display unit 14.In FIG. 11, a device data display screen 51 in the step [1] isillustrated. From the device data display screen 51 in the step [1], itcan be confirmed that the value of the device D1 has reached 110 as aresult of adding 10 to the device D1.

It can be specified that the incorrect operation is caused by adding 20to the value of the device D1 in the step [2] based on the device datadisplay screen 53 in the step [3] illustrated in FIG. 9, the device datadisplay screen 52 in the step [2] illustrated in FIG. 10, and the devicedata display screen 51 in the step [1] illustrated in FIG. 11.

As described above, by displaying the device data output to the memorycard 11 on the engineering tool 12, the device data can be confirmed byusing a graphical user interface for displaying the SFC program. Thetroubleshooting can be more easily performed by confirming the devicedata by using the graphical user interface for displaying the SFCprogram than a case where the device data is confirmed based onnumerical data by using spreadsheet software.

In the above operation, the device in the step is analyzed when theoperation output in the step is executed. However, when the programmablelogic controller is turned on, the device in each step of the SFCprogram may be analyzed. If the device in each step of the SFC programis analyzed when the programmable logic controller is turned on, theprocessing in step S33 for determining whether the device in the stephas been analyzed and the processing in step S34 for analyzing thedevice in the step can be omitted at the time when the SFC program isexecuted. Therefore, an execution speed of the SFC program can beincreased. However, the storage region for each step is secured in theSFC device data storing unit at the time of the analysis of the devicein the step. Therefore, if the device is analyzed when the programmablelogic controller is turned on, a storage capacity which can securedevice data storing units for all the steps in the SFC program isrequired for the storage device for realizing the SFC device datastoring unit. Therefore, it is preferable to determine whether thedevice is analyzed when the programmable logic controller is turned onbased on the number of the steps in the SFC program and the storagecapacity of the storage device.

According to the first embodiment, since the device data is collectedfor each step in the SFC program, all the device outputs in the step canbe displayed, and the operation process of the device can beretroactively confirmed.

Second Embodiment

FIG. 12 is a diagram illustrating configurations of a programmable logiccontroller and an engineering tool according to a second embodiment ofthe present invention. A programmable logic controller 61 according tothe second embodiment is different from the programmable logiccontroller 1 according to the first embodiment in that an SFC parameterstoring unit 5 for storing whether to collect device data and parametersfor respectively setting ranges of the steps to be collected for eachblock is included. In the second embodiment, an SFC program executingunit 4 executes an SFC program according to the settings of the SFCparameters.

A hardware configuration of the programmable logic controller 61 issimilar to that of the programmable logic controller 1 according to thefirst embodiment. Therefore, the SFC parameter storing unit 5illustrated in FIG. 12 is realized by a storage device 23.

As illustrated in FIG. 12, an engineering tool 62 according to thesecond embodiment is different from the engineering tool 12 according tothe first embodiment in that an SFC parameter setting unit 16 forswitching whether the device data is collected and setting a range of astep in which the device data is collected is included.

A hardware configuration of an information processing apparatus forrealizing the engineering tool 62 according to the second embodiment issimilar to that of the first embodiment. Therefore, the SFC parametersetting unit 16 illustrated In FIG. 12 is realized by executing anengineering tool program 38 stored in a storage device 33 by using amemory 32 as a work area by an operation device 31.

FIG. 13 is a diagram illustrating an exemplary SFC parameter settingscreen of the engineering tool according to the second embodiment. In anSFC parameter setting screen 70, a device data collection setting field71 and a device data collection range setting field 72 are provided. Thedevice data collection setting field 71 is provided in a form of apull-down menu, and can alternatively select “to collect the devicedata” or “not to collect the device data”. When the device datacollection range setting field 72 is selected, a device data collectionrange setting dialog 73 is displayed in a pop-up. The device datacollection range setting dialog 73 includes a block name specifyingfield 731 and a collection range specifying field 732. In FIG. 13,setting is made to collect the device data between a step [0] to a step[3] of a block [1].

FIG. 14 is a flowchart illustrating a flow of a device data collectionoperation of the programmable logic controller according to the secondembodiment. Initial processing in step S11′ is different from theinitial processing in step S11 according to the first embodiment in thatprocessing for obtaining a parameter set to the SFC parameter settingunit 16 by the engineering tool 62 is included.

The flow of the SFC program execution processing of the programmablelogic controller 61 according to the second embodiment is similar tothat of the first embodiment.

FIG. 15 is a flowchart illustrating a flow of block start processing ofthe programmable logic controller according to the second embodiment.Compared with the block start processing of the programmable logiccontroller 1 according to the first embodiment, the block startprocessing in the second embodiment is different from the block startprocessing of the programmable logic controller 1 according to the firstembodiment in that step S36 which is processing for confirming an SFCparameter and step S37 which is processing for confirming whether thedevice data is within the device data collection range are included.

In step S36, the SFC device data collecting unit 8 confirms whether theSFC parameter is set to collect the device data. The SFC parameter isset to collect the device data, the result in step S36 is Yes, and theSFC device data collecting unit 8 confirms in step S37 whether thedevice data is within the device data collection range. If the devicedata is within the device data collection range, the result in step S37is Yes, and the procedure proceeds to step S33.

If the SFC parameter is set not to collect the device data, the resultin step S36 is No, and the processing is terminated. If the device datais out of the device data collection range, the result in step S37 isNo, and the processing is terminated.

When the device data in the step is collected with no conditions, a scantime of the programmable logic controller is deteriorated. Theprogrammable logic controller 61 according to the second embodimentswitches whether to collect the device data in the step by SFC parameterfor each block and can set the device data collection range for eachstep in a case where the device data in the step is collected.Therefore, the device data can be collected when the troubleshooting isrequired. Therefore, the deterioration in the scan time of theprogrammable logic controller 61 at the time of the normal operation canbe prevented.

The structures illustrated in the above embodiment indicate exemplarycontents of the present invention and can be combined with other knowntechnique. Further, the structures illustrated in the embodiment can bepartially omitted and changed without departing from the scope of thepresent invention.

REFERENCE SIGNS LIST

1, 61 programmable logic controller, 2 device

data collection function unit, 3 SFC monitor unit, 4 SFC programexecuting unit, 5 SFC parameter storing unit, 6 SFC device analysischeck unit, 7 SFC device analyzing unit, 8 SFC device data collectingunit, 9 SFC device data storing unit, 10 SFC device data outputtingunit, 11 memory card, 12, 62 engineering tool, 13 SFC output filereading unit, 14 SFC display unit, 15 monitoring result displaying unit,16 SFC parameter setting unit, 21, 31 operation device, 22, 32 memory,23, 33 storage device, 24 memory card writer, 25, 37 communicationdevice, 30 information processing apparatus, 34 display device, 35 inputdevice, 36 memory card reader, 38 engineering tool program, 41 block[1], 42 block [2], 43 block [3], 51, 52, 53 device data display screen,70 SFC parameter setting screen, 71 device data collection settingfield, 72 device data collection range setting field, 73 device datacollection range setting dialog, 91, 92, 93 storage region, 731 blockname setting field, 732 collection range specifying field.

1. A programmable logic controller for executing a sequential functionchart program including a plurality of blocks, each including a firstbasic unit indicating an operation output and a second basic unitindicating a transition condition, the programmable logic controllercomprising: a processor to execute a program; a memory to store theprogram which, when executed by the processor, performs a device datacollecting process to collect device data of a device included in anactive first basic unit for each scan at the time when the sequentialfunction chart program is executed; a device data storing unit to storethe data collected by the device data collecting process; and a devicedata outputting unit to output the data stored in the device datastoring unit to a storage medium as a file for each of the first basicunits or the blocks.
 2. The programmable logic controller according toclaim 1, further comprising: a parameter storing unit to store aparameter in which whether to collect the device data and the firstbasic unit for collecting the device data are set for each of theblocks.
 3. An engineering tool for monitoring an operation of aprogrammable logic controller that executes a sequential function chartprogram including a plurality of blocks, each including a first basicunit indicating an operation output and a second basic unit indicating atransition condition, the engineering tool comprising: an output filereading unit to read device data from a storage medium to which devicedata of a device included in an active first basic unit at the time whenthe sequential function chart program is executed by the programmablelogic controller has been written in a file for each of the first basicunite or the blocks; a processor to execute a program; and a memory tostore the program which, when executed by the processor, performs todisplay the device data read by the output file reading unit bysuperimposing the device data on the sequential function chart.
 4. Theengineering tool according to claim 3, wherein the program which, whenexecuted by the processor, further performs to set a parameterindicating whether to collect the device data and a range of the firstbasic unit for collecting the device data for each of the blocks.
 5. Anon-transitory recording medium which stores an engineering tool programcausing a computer to monitor an operation of a programmable logiccontroller, and to execute: a process of reading device data from astorage medium to which the device data of a device included in anactive first basic unit when a sequential function chart program hasbeen written in a file for each of first basic units or blocks by theprogrammable logic controller for executing the sequential functionchart program including the plurality of blocks, each including thefirst basic unit indicating an operation output and a second basic unitindicating a transition condition; and a process of superimposing theread device data on the sequential function chart and displaying thedata.
 6. The non-transitory recording medium according to claim 5causing the computer to execute: a process of setting a parameter thatindicates whether to collect the device data and a range of the firstbasic limit for collecting the device data for each of the blocks.